Conventionally, there are multiple time zone display watches, such as a world-clock display found as a kind of digital watches, which can display different times in addition to the current time. As is commonly known, such a digital watch displays time other than the current time by switching the display by the operation of a push button or the like.
Recently, watches which can indicate multiple times using hands for display have also been developed. Specifically, these watches are provided with several display sections, in which the times for other time zones are directly displayed as local times, in addition to the current time display for the locality in which the watch is being used, or, these are watches which display times for other time zones, to which a different-time display function has been added, with the display being switched by the operation of a push button or the like.
The structure of the movement for a hands-display type of watch, on which a plurality of times is displayed in a multi-display section as outlined above, utilizes a plurality of small, finished movements, normally used on bracelet-type watches for women, or the like, which are secured to the watch case and housed at specified locations on a convex section provided on an inner frame of synthetic resin, with a face plate and hands mounted on the individual movements. Thus, multiple hands are used to indicate a plurality of time zones. A watch with this type of structure for displaying many time zones has, therefore, the same number of time display sections as the number of watch movements. The wearer can readily use both a current time display and other-zone time displays by optionally selecting the plurality of time display sections.
The times on this type of watch are adjusted using crowns on an extended line connected to the center section of the timepiece and the center of each of the various time display sections, as external operating means. The wearer can therefore set the various times by pulling out and operating the crown matching the respective time display section.
Further, among multi-time-zone watches with a plurality of crowns, a specially designed watch, which places the crowns close to the band clasp in the case of a watch in which the crowns overlap on the wrist band, either top side or under side, has been developed.
However, these multi-time-zone watches with hands-display-type have a difficulty in aligning a plurality of small movements mounted on the concave housing section of the inner frame, so that it tends to invite the occurrence of a temporary-stoppage phenomenon by interference or deviation of the clearance hole of a hour wheel for attaching an hour hand on the watch-face, or tends to give an awkward appearance.
In addition, because the multi-time display consists of a plurality of small movements, a large number of steps in the assembly process is required, and because the large number of parts the cost of the watch movement becomes rather high. It consequently leads to a high price wrist watch. Also, the watch becomes rather large in shape in comparison with other watches.
Further, the hands in the multi-time display sections must be independently adjusted. For example, when the above-mentioned time display sections are positioned right above or right below a part of the watch, the crowns are difficult to operate, making it extremely difficult for the wearer to set the hands. Also, because the various display sections are driven independently, reading errors may be caused from errors in operation the crown by the wearer.
Another structure used in a movement for a hands-equipped watch for indicating multiple times is the type as described in FIG. 1 and FIG. 4 of Japanese Utility Model Laid-open Publication No. 120684/1989. In the watch described in this patent publication, the gear train extends in four directions from an hour wheel so that many different times are displayed by a plurality of hands on a plurality of display wheels positioned in concentric circles.
However, in a hands-equipped watch for indicating multiple times shown in FIG. 1 of Japanese Utility Model Laid-open No. 120684/1989, the gear train must extend in many directions from the hour wheel and much work is required in the manufacturing of the gear train and the assembly of the watch movement and the like because a pair of intermediate wheels (referred to as planetary wheels in the publication) must be placed on one display wheel. This results in an increase in costs.
In another embodiment shown in FIG. 4, for example, when a hands-equipped multi-time display watch is planned to manufacture, there is a danger of misreading the minute units for the hour characters. Practically, the moving direction of the hands for displaying the times in other zones is the reverse of the direction of rotation of the hands for the current time.
Also, a planetary wheel method Lot a normal hands-equipped watch with three hands and the like to which a time difference display function is added has been proposed for an embodiment in Japanese Patent Laid-open Publication No. 30676/1980. The embodiment of this method comprises a position-regulated dual wheel with 11 teeth, a planetary wheel, and an hour wheel with 12 teeth to which an hour hand is attached. In this method, the planetary wheel moves along the periphery of the dual wheel in line with the rotation of a second wheel which rotates once in 60 minutes so that the hour wheel is rotated at a reduction ratio of 1/12.
However, in the watch with a time adjustment mechanism proposed in Japanese Patent Laid-open Publication No. 30676/1980, the hour hand in the normal display of the current time is moved for Lime adjustment when viewing the local time in another time zone on the watch. This creates the problem that it is difficult to determine the local time because the current time has been switched.
On the other hand, in a day-adjustment mechanism for a calendar gear train structure on a watch with hands for multiple time displays rotational force from a watch drive gear train is transmitted to a day rotary wheel which engages the hour wheel so that a day plate is fed by the engagement of a day feed hook, provided on the day transfer wheel, with the teeth on the day plate. In this day feed mechanism, in order to ensure that no more than two of the teeth on the day plate are advanced during the day feed, the shape of the day rotary wheel is deformed by the provision of an obstruction on the outer periphery of the day rotary wheel, so that only o:,.e tooth is engaged, advancing exactly one day's amount.
Also, a fast feed mechanism in a calendar gear train structure for a conventional hands-display watch works, when the crown is rotated at a one-step pull state, with a fast adjustment transmission lever via a transmission lever which engages the rotary action of a hook provided on a sliding pinion, so that the day plate is advanced by the day feed hook provided on the fast adjustment lever.
The day feed mechanism in the former calendar gear train structure for the hands-display watch is provided with an outer wall or an obstruction on the outer periphery of the day rotary wheel. By deforming the shape of the day rotary wheel, a feed hook which projects to engage the day plate controls the amount of engagement with the teeth of the day plate so that no more than two of the teeth of the day plate are fed in one day. This mechanism, however, entails a drawback that the day rotary wheel must have a complicated shape to be deformed.
Also, the fast adjustment mechanism in the latter calendar gear train structure for the hands-display watch must be linked with the sliding pinion, the fast adjustment lever, and the day plate. Therefore, not only is a large number of parts required, but there is also the drawback that it is difficult to obtain reliable operation with the large number of parts. In addition, although this mechanism is appropriate for the case of teeth with a large pitch such as a ring-shaped day plate positioned on the outer periphery of the watch module, it has a drawback that it is difficult to adjust small gears because the range of action of the feed hook for the fast adjustment lever is widened.
Accordingly, an object of the present invention is to provide a watch with multiple time displays without the problems associated with a conventional watch with hands for multiple time displays.
Specifically, an object of the present invention is to provide a low-priced watch with hands for multiple time displays in which an increase in the diameter of the watch is avoided, and which allows a superior design and good operability so that the wearer finds it easy to use.
A further object of the present invention is to provide a watch with hands for multiple time displays equipped with a highly reliable calendar gear train structure in the case where hands are used for indication the calendar.